1. Field of the Invention
The present invention relates to an acrylic pressure-sensitive adhesive composition, and an acrylic pressure-sensitive adhesive layer and an acrylic pressure-sensitive adhesive tape each having the acrylic pressure-sensitive adhesive composition.
2. Description of the Related Art
Because acrylic pressure-sensitive adhesive tapes each having an acrylic pressure-sensitive adhesive layer are excellent in adhesiveness, such as pressure-sensitive adhesive force, resistance to resilience, and holding property (cohesive force), and further excellent in aging resistance, such as heat resistance, light resistance, weatherability, and oil resistance, the acrylic pressure-sensitive adhesive tapes have been conventionally used in wide applications. In particular, the acrylic pressure-sensitive adhesive tapes having such properties have been widely used as joining materials in various industrial fields, such as home electronic appliances, building materials, and automobile interior and exterior materials. Accordingly, the acrylic pressure-sensitive adhesive tapes are required to be adhered, with high reliability, to various adherends (objects to be joined) including: metallic materials, such as stainless steel and aluminum; various plastic materials, such as polyethylene, polypropylene, polystyrene, ABS, (meth)acrylic resin, and polycarbonate resin; and glass materials, etc.
A method of adding a tackifying resin (tackifier) to an acrylic pressure-sensitive adhesive composition that forms an acrylic pressure-sensitive adhesive layer is known as a method of enhancing the adhesiveness of an acrylic pressure-sensitive adhesive tape to an adherend. Patent Documents 1 and 2 disclose acrylic pressure-sensitive adhesive compositions in each of which rosin or a hydrogenated petroleum resin has been added, as a tackifying resin, to an acrylic polymer.